24 ORGANS OF SENSE. 



The orbits are incomplete, and generally there is a third eye-lid 

 which is semi-transparent, and moves transversely. 



13. The structure of the ear is less complicated than in the 

 superior animals. The external ear is almost always entirely 

 wanting ; there is no auditory canal, and the tympanum is on a 

 level with the head and exposed, or concealed beneath the skin. 

 The organ of smell is but little developed ; the nasal fossae are 

 generally very small, and the pituitary membrane the lining 

 membrane of the nose presents few, or no folds. 



14. Most reptiles swallow their food without chewing it, and 

 their sense of taste appears to be very dull. The tongue is some- 

 times thick and fleshy ; but, in general, it is thin, dry, very pro- 

 tractile, and often bifid ; it sometimes becomes an organ of pre- 

 hension, the play of which is very remarkable. 



15. Few reptiles live exclusively upon vegetable matter. 

 Almost all of them are carnivorous, and, with some exceptions, 

 they hunt living prey which they generally swallow whole : the 

 selection of the animals upon which they feed, is, in a measure, 

 regulated by the dimensions of their mouth. Most of them drink 

 but little, and they can fast for a very long time without incon- 

 venience. 



16. The mouth is deeply cleft, and generally armed with teeth, 

 which are sometimes found in the palate as well as in the jaws ; 

 they are almost always of a conical form, and, in general, in 

 place of being lodged in alveoli, they are soldered, as it were, by 

 their base to the bone that sustains them. In some reptiles that 

 are without teeth, the jaws are covered by a horny plate, the 

 edges of which are trenchant, like the beak of a bird ; but they 

 never have fleshy and moveable lips like mammals. 



17. Glandular organs in considerable numbers ordinarily 

 surround the mouth of reptiles, and pour into it either a gluey 

 humor or saliva ; sometimes there are also glands, very closely 

 resembling salivary glands, which secrete a violent poison. 



18. As it is not necessary for their food to remain in the 

 mouth for mastication, a veil of the palate would have been, in 

 general, useless, and, in fact it rarely exists. In most of these 

 animals, the pharynx is not distinct from the mouth, and often 



13. Is the organ of hearing the same in Reptiles as it is in mammals? 

 Is the sense of smell acute or otherwise ? 



,* 14. Have Reptiles a strong sense of taste ? What is the character of the 

 tongue ? 



15. Upon what do Reptiles generally feed ? Do they drink much ? 



16. What is the form of the teeth of Reptiles ? Where are they situate ? 

 Do they exist in all Reptiles ? 



17. What is the character of the glands found about the mouth ? 



18. Have Reptiles any veil of the palate ? What is the character of tho 

 pharynx ? What are the general characters of the digestive organs ? 



